BARTLESVILLE, Okla. — T.W. Shannon will be Oklahoma’s first black senator if he wins the Republican nomination and is elected in November, but the quiet campaign stirring here about Shannon’s racial loyalties is not aimed at the African-American branch of his family tree.

Shannon, whose first name is Tahrohon, is a member of the Chickasaw Nation, the most influential tribe in a state where Native Americans are not merely the inheritors of a poignant history but also the state’s largest nongovernment employer outside of Wal-Mart.

Most of those jobs are connected to Oklahoma’s 110-and-counting casinos, which are becoming as familiar here as oil derricks. Yet the gambling revenue that has showered millions on some of the state’s Native Americans has also bred resentment over the tribes’ expanding footprint. Now, as Shannon vies to make history, he has become both the political beneficiary of the tribes’ newfound wealth and a target for complaints about Native American sovereignty and possible competing loyalties.

Beyond Oklahoma, Shannon, a 36-year-old former state House speaker, has the potential to become a sensation in a party desperate to shed its old-and-white image. Some prominent conservatives have embraced his candidacy.

While identity politics — about race, religion or gender — has been a defining element of both parties for generations, Shannon adds a rare dimension. And he says he is uneasy about being the latest emblem of Republican diversity.

Shannon, whose father is Chickasaw and mother is black, would be only the second enrolled tribal member to join the Senate in nearly 100 years; Ben Nighthorse Campbell of Colorado was first, in 1993. Shannon has received tens of thousands of dollars directly from Chickasaws and other tribes. And an independent group, Oklahomans for a Conservative Future, has spent more than $435,000 on his behalf since March. The group has received contributions from Indians, according to Republicans familiar with the donors who were not authorized to speak for the group.

As he has emerged as a formidable candidate to win the seat held by Sen. Tom Coburn, a Republican who is retiring, Shannon also has prompted a revival of old grudges about citizenship and identity.

“Btw, the Indians aren’t Oklahomans,” Robert Dan Robbins, a rancher and prominent supporter of Shannon’s chief primary opponent, Rep. James Lankford, wrote on his own Facebook page. “They are a member of their own nation and are suing the state of Oklahoma over water rights and other things as well.”

A Tea Party group, in an open letter about Shannon, warned, “He has too many masters to serve,” and listed “Indian tribes” and Rep. Tom Cole, a fellow Chickasaw and establishment-oriented Oklahoma Republican, among his suspect influences.

Unlike many states with significant Indian populations, Oklahoma before statehood was made up of Indian territories, and members of its tribes are culturally integrated and do not live on reservations.

Still, tensions that stem from the tribes’ unique status are evident. “When someone says that Indians aren’t real Oklahomans I guess they forgot that Oklahoma is Choctaw for ‘red people,’” said Cole, neutral in the race but a mentor to Shannon, who was once his driver. “Look, Indians have been here long before anybody else, and most of them didn’t exactly come here by choice.”

Shannon is more cautious when discussing his background. In an interview after an early-morning Rotary Club visit in this small, northeastern Oklahoma town, best known as the ancestral home of Phillips 66, he emphasized that he was “very proud” of his heritage, while carefully noting that it does not define him entirely.

“I’m an American first, and that’s the most important thing,” said Shannon, who was first elected to the state House of Representatives in 2006.

Such efforts at reassurance — along with ads like the one promoting legislation he sponsored requiring that welfare recipients work — may be necessary in a state that bears such history as the Trail of Tears. But Oklahoma, at the geographic and cultural intersection of the Great Plains, the South and the West, is the same state that once elected African-American, Native American, Jewish, Catholic and Mormon candidates to high office in the same year, two decades ago.

The African-American elected in 1994 was J.C. Watts, a former University of Oklahoma quarterback who became the Republican Party’s highest-profile black official as a member of Congress. Shannon recalled advice from Watts, who told him, “If you make it your issue, if you make it the focus of your campaign, then it will be.” His racial background, Shannon said, “is just one part of my experience — it’s not the defining moment.”

So Shannon is not just seeking to put the state’s deeply conservative Republican primary electorate at ease and pre-empt a nascent whispering campaign. He also wants to be something more than a handy symbol at a moment when his party’s crippling lack of success among nonwhites and the presence of the first black president have made race central to the country’s politics.

But that may not be easy.

“His name alone!” Sarah Palin exclaimed at a large, nearly all-white rally of supporters for Shannon in Tulsa last month. “The Democrats accuse us of not embracing diversity? Oh, my goodness, he is — he’s it. He is the whole package.’’

But other conservatives are plainly uncomfortable with such tactics. Sen. Ted Cruz, R-Texas, who was also at the rally, said in an interview, “Rather than engage in identity politics and smear campaigns, which is the specialty, sadly, of the modern Democratic Party, we ought to be discussing how to turn this country around.”

Yet the statement that Shannon’s election would make is very much on the minds of Oklahoma Republicans, some of whom think he could pierce stereotypes about their state and party.

“We need people that can relate to the average American, and the average American is not the average American from 1955,” said state Sen. David Holt, a Republican. “You’ve got to project a face from your party that reflects America, and America is changing.”

There is also something compelling about the prospect of elevating a native son who made his name here, and not beyond Oklahoma’s borders, as did a long list of exports including Mickey Mantle, Jim Thorpe, Ralph Ellison and Woody Guthrie.

Lankford, the most formidable other Republican in the race, recognizes Shannon’s symbolic appeal and is already moving to frame the question in his own terms. “What are Oklahomans looking for?” Lankford said in an interview. “Are they looking to have a celebrity, or are they looking for somebody to be able to solve their problems?”

But, chatting in a Tulsa coffee shop just up the road from a Creek Nation casino, Lankford acknowledged that the financial backing Shannon had received from the tribes had given his opponent a boost.

“They’ve been pretty clear that they want to have a tribal member in the Senate,” said Lankford, a member of the House leadership who led a large Baptist summer camp in his heavily Baptist state before going to Washington in 2010.

Former Gov. Frank Keating, a Republican, said: “You’ll have the Baptists embracing Lankford and the tribes embracing Shannon. That’s quite a tug of war between two redwoods.”

Oklahomans for a Conservative Future, the group advertising on Shannon’s behalf, is structured under a section of the tax code that does not require disclosure of its donors. An official with the group would not discuss the identities of its donors, but people familiar with the contributions acknowledged that it had received tribal money.

It is one of the first measures of Native Americans gaining political strength, a role likely to endure whether or not Shannon wins.

“Most people didn’t worry about the Indians in part because they were everywhere, they sort of looked like everybody else, they sort of lived like everybody else,” said Keith Gaddie, a University of Oklahoma political science professor. “Nobody cared about Native Americans until they got money.”